Pipe thread gauge



Patented July 24, 1951 UNITED STATES OFFICE PIPE THREAD GAUGE Myron E.. Steczynski,. Chicago, Ill.`,. assignor.` to;

Niles-Bement-Pond Company, West.Hartford`, Conn., a corporation of New Jersey ApplicationAugust. 14, 1944; Serial N0.- 549,552+` 4 Claims.

This. invention relates. to gauges for testing. the accuracy ofthe pitch diameters of externaland internal taperedpipe threads, and the like.

One. of the objects of. the invention is the provision of a, new. andv improved pipethread gaugeA havingnovelmcans for resetting or adjusting the indicating mechanism so that. the gauge may be set by the aid of a masterv gauge to. indicate approximately accurate readings.

Another object of. the inventionis the provisionof new andV improved gauge .mechanisms that will test. the accuracy of the pitch diameters of tapered pipe threads with great accuracy.

A` further object' of the invention is the provision of a set of. tapered. pipe thread gaugesv having a micrometer reading indicator for `indicating at a glance the. accuracy of they pitch diameters of internal and externaltapered pipe threads expressedin turns and partial turns of the threads;

A still further object of thev invention;` is the..

provision ora new and improved gauge. that, is

very small in size andlight in weight, `and that has the scale so' locatedthat the readingsmay be made at a glance even to withinvfractions of a turn of the threads.

A still further object of' the. invention. is the provision of new andimproved mechanismifor testing the accuracy of pitch diameters of.

threads; that is simple' in construction, Aeasily assembled and adjusted, composed of few parts;V

of construction used fortesting andrneasuring"r the accuracy of the threads;

Fig. 6 is a vertical section thereof;

Fig. 7` shows the indicatingscalefon thegauge illustrated in Figs; 5 andas developed; and

pitch diameters of-v internal Fig; S shows the micrometer scale, developed.

It is customary tomeasure external taper'pipe threads with .ring gaugesV and internal taper.. pipe and further `objects and advantages of of a gauge-for testing 3 shows the indicating scale employed with threads with plug gauges. The gauges, are screwedonto the .part until. they` are fairly. tight, and.u then the. depthto which the two. engage` is observed. Inthe caseof a` ring gauge..measur ing.. an. external` pipethread, the thread` size is said` to bebasicwhen theend` of thepipe is perlectly` flush with the face of. thelgauge. In the case. of,` a. `plug gauge .-measuring an internal. pipe.' thread, the thread.V size issaidto be basiowl'ien` thenotchon the. pluggau-ge is perfectly` flush.

withtheiace offthetapped hole. Any deviation from basic position is referred.V tain terms of. the

number of turns. or fractionr of a turn necessary to bring the two reference'planes. together.

If.' the external. threadis toosmall in pitch diameter, or the internalthread. is too largeso that` the parts screw in too far, the gauge canthen be unscrewedtc. the approximate basic position and.` the number oifturns actually counted. If,.

however, the `external thread is. too large in` pitch diameter, or the internal threadis too small, the parts will"not screw in'far enough.. It is then necessaryto count and estimatefthe number of threads which separate the common referencel planes: No exact means is` provided to obtain an exact reading, unless perhaps. a` depth micrometer can be used to measure the separation of the two. reference planes. It is common .practiceto limit the deviation fromlbasic size to onev turn large or one turnsmall on both external and internal pipe. threads.

The object of this invention is. to. provide a.

meansfor. reading. accurately the size oan external or.. internal tapered pipe thread, regardless oi whether thepartis. over basic size or under basic size.` One. arrangementisfor holdinga standard ring-gauge to. read thetsize of external..` pipethreads, while. the .other arrangement, is for holding a` standard` plug` gauge. to readthe size of internal `pipe threads.-

Besidesusing .this invention as an adjunct to basic standard gauges for measuring those threads which are engaged. by hand. only, they canllikewiseabeused ,with gauges that measure the additional threads which are engaged when tightened. with.Y a. Wrench, thereby, giving. an indication of. taper; also. these gauges can be'usedf` with. semi-truncated gauges which` indicate. the

form.. of the thread.; and linally, they can be used. with. .fully truncated. gauges. which measure` theA amount of. truncation. at: thecrests of the. threads. close readings for comparisonf-therefore thev necessity ci accurate determination is apparent.

All gauges used for. actual .che.c1\:ing;,'` i. e;., work-.-

All. these.- measurements involve ing gauges, are subject to apparent wear over a usable range, and this amount of wear must be taken into account at every gauging operation. It is customary to extend the wear to half a turn on both ring and plug gauges for pipe threads. This invention depends for its setting upon a master gauge mating with the working gauge, and will, read correctly from the master gauge even if the working gauge is made or is worn from the true basic size. In this way the working gauge can be set and reset to read accurately, independently of the wear on said gauge.

The conventional tapered pipe thread gauge is usually calibrated to indicate what is termed basid maximum and minimum condition of the threads. In other words, if the pitch diameters of the threads are correct the scale will read zero or basic, and if the pitch diameters along the threaded stem or anvil support 2| by this jam nut 25. The micrometer indicator member 24 and nut 25 constitute what may be termed a handle 39 for adjusting the gauge mechanism. This micrometer indicator member has a counterbore 28, forming a sleeve portion 24a that telescopes the scale supporting member I9.

The stem or scale supporting member I9 is provided on its exterior with a. stepped scale 23 (Fig. 1) which may be on the periphery thereof, and the steps are numbered from I to 4 from a neutral or basic line marked 0, as shown as developed in Fig. 3. There is a scale both above and below the zero line, as shown at 23 and 23a, respectively, in Fig. 3, and as will presently appear. Each step indicates a complete turn of the thread that is being tested, which means that the pitch diameters of the tested are greater they are designated plus or maximum; if below, they are regarded as minus of minimum.

These calibrations are expressed in terms of the number of threads or turns above or below a predetermined or basic position of the member being tested, as compared with a master gauge. The present invention indicates the theoretically accurate `pitch diameters of the threads marked zero on the scale, as well as the number of turns and fractions thereof above or below the Zero point. This results in more correct readings being made, and greater accuracy in information obtained from the tests.

Referring now to Figs. l to 4 of the drawings, the reference character I0 designates, generally, the gauge for testing the accuracy of the pitch diameters of tapered threads vof an externally threaded member. The gauge comprises a head member II. forming a ring member having internal threads I2 of the required taper and arranged axially of the head II. Suitable means are provided for holding or positioning the head, and for rotating the same for applying it to a tapered threaded pipe or other member. In the form of construction shown in these figures, a holder or head support I3 is employed for this purpose. The holder or head support I3 may be of any suitable material, such as an organic plastic, either thermo-setting, as the phenol or urea aldehydes, or thermo-plastic of high melting point, as Lucite or the like, which may be pigmented to give any desired tint or color; or it may be of metal, if desired.

The holder or head support I3 is provided with a recess I4, having an outer counterbore or enlarged recess I5 forming a ledge or seat I6 on which the peripheral ange I1 of the head IL is adapted to seat. The head is rigidly held in the` counterbore on the ledge I 6 by any suitable means, such as the set-screw I8. The head support I3 has an axial extension or scale-supporting member I9, which is provided with an axial internally threaded bore for receiving one end of a threaded anvil support 2|.

Suitable means are provided for indicating the accuracy of the pitch diameters of the threads, as will now be described. The anvil support or threaded member 2I is threaded into the extension or scale supporting member I9, and carries on its inner end an anvil 22 which is adapted'to threads are substantially accurate, or are above or below the basic or accurate pitch diameter. A line 20 is also provided on the scale supporting member which extends longitudinally of the stem or extension I9, for assisting in determining the partial turns of the threads, as will be explained below. In reading the scale the notation for the step appearing just inwardly of the inner edge of the indicator member 24 indicates the reading in full turns of the threads.

Instead of a stepped notation printed or impressed on the surface ofthe scale supporting member I9 portions of the wall of said member may be cut away to form the steps I, 2, 3 and 4 in the marginal edge of the opening formed by y the cut-away portion. The full turns are visible over the inner edge of the indicator member 24.

Suitable means are also provided for indicating the partial turns of the thread that may be above or below the basic or zero reading, as will now be described. The micrometer indicator member 24 is graduated, as shown at 21 in Fig. 1, and as developed in Fig. 4. One oi these marks is indicated zero, and since there are eight divisions each mark will differ from the other by an eighth of a turn of the micrometer indicator member, as

fmeasured from the line 20 on the scale supporting member I9. A complete rotation of the micrometer indicator member 24 advances that member a distance equal to the lead of the thread, i. e., the distance between two notations on the scale in Fig. 3.

In practice two notations are provided. One of them, viz. the one above the line m-n in Fig. 4, indicates plus reading, i. e., the extent that the pitch diameters of the threads being tested are greater than the standard as measured by the gauge and expressed in turns, or partial turns, of the threads; while those below the line indicate the minus reading, i. e., they, taken in connection with the stepped notations at the left in Fig. 3, indicate to what extent the pitch diameters of the threads of the tested pipe are smaller than the standard or basic In setting the gauge the handle 38 (Fig. 2) is rotated counterclockwise until the anvil 22 is withdrawn beyond the point where it will interfere with the insertion of the plug of the master gauge. The plug of the master gauge is then screwed into the head I I to form a snug nt. The anvil 22 is then brought into contact with the inner endof the plug of the master gauge, after which the micrometer indicator 24 is adjusted along the anvil support until the inner edge of the member 24 indicates the line Ii-Il and the zero on the scale 2'! (Fig. 4) is opposite the line 2|] (Fig. 1). The set or lock nut 25 is now tightenedfor'holding the-@indicator member Z4 rin ilxed! position ontlie anvilsupport 21H.

InA the Hoperationloff the: device the adifustingI member 25- and?` indicator` member Zei areturned together" t'ol partiallyE withdrawl the-lanvilr support 2| from the holder, after which the tapered threaded memberto be tested isscrewed intb'lthe'lieadi' il `until af-snug iltis obtained: The handle f fis new turned right-mander until' the anvil 2z? brought into" contact e withf the4-` inner f indicator, and the number visible on'sucn arsca'le` justabove the' upper edge of themembeird; ass

viewed in Fig'. 1, willi indicate thefnumber of" threadsY above orbelowf` the zeroi marit. The scale issoy constructed that# thefractional* part oi a turn will be indicated"by the micrometer in dicator marks 27, as compared with the mark or linei2|l`asshowninFig; 1;

The position ci the indicatingmember 24, when a tapered thread meinberds screwed into the head |l making a tightfiitxtherein..andy,simultaL neously engaging the anvil 22 ontliemember. 2|., indicates ata` glance whether the-pitch diameters of the threads are basic or above or be" low basic If, when the member to betested" is screwed?intothe'head I7',` making a snug nt; the micrometer'indieator must be' turned idghthanded beyond zeroh reading to cause the anvil toengage" the inner end of` the" threadedY merm beni. then the pitch"4 ,diameter ofthe threaded memberistoo `greatto beaccurate. On tlieotlier' hand', if it is necessary to` unscrew theJ sleeve member 2| to such an extent that the reading on the scale must be below the zero mark in Fig. 3, then the pitch diameter of the threads is too small to be accurate. Usually the tolerances are one, sometimes two threads either way, and the tester can tell at a glance whether the threaded member should be discarded.

The tolerances may be much less, especially when the tested member is to be employed in exceedingly high pressures, as in hydraulic equipment, and the like, where pressures are sometimes very great. The micrometer scale reading .mech-` anism under such circumstances becomes quite valuable, since the gauge is quite accurate in its measurements, and the gauge may be reset with a minimum of time and eiort.

In Figs. 5, 6, 7 and ti is shown a modified form of construction for use in measuring internal threads of members that are to be tested. In this form of construction a head member 3| of the gauge 50 is provided with external threads having a substantially accurate pitch diameter, and this head has an extension or shank 32 which is adapted to irictionally engage in a corresponding tapered opening in an externally threaded head support 33. By providing a tapered frictional engagement for this shank, interchangeable heads may be provided for use with the same handle or support.

A scale supporting member 34 is threaded on the lower end of the head supporting member 33, and is held in adjustable position along the same by a cap or set nut 35. The scale supporting member 3A is provided with a scale 3 corresponding to the scale 23, 23a, shown in the previous construction. This scale may, if desired, be stepped, and may be formed on the peripheral surface of the scale supporting member 34, or

6i! formed on the marginrofaiwindoworfcuteaway portionl in the wall of saidlmember 1134;' asin the construction described above. The steps are arfranged aboveand'below"allzerov or.' basic line, asi; described above:` Since' the scaleeissimilarztoi theV sealer-23; 23a, already'described, itisrnotthought necessarysto repeat the'description:

Thef steps-may: be numbered. 1,. 2, 31 andi litin eachV direction from the basic or zero.. line lle-4), asshown'in Fig-7, andi asexplained in .con-f n'ectionswithfthev developed scale'shown" in Fig. 3..

A. micrometer indicator' and: anvil support 4D- is provided for: indicating' the-'accuracy 'of i the partial turns of thethreads` of an internal: threaded member.' This: supporting member 4|) has. ani

eniargedfcounterboref 33, so. that it may telescope 'fthe scale supportingfmember 34; The upper." of the. member 30 isralso: providedwithz a;

G7, end :i counterbore head 3 I Ther upper end?` oflttlie` supporting:` member.' 4|!` `Ztl for providing a' clearancezfor'the supporter an; anvil.A lil integraltherewitl'i,` andi.k

whiclrisfadapted .torbef brought into .contactawithv an'l internal threaded member? to be` tested. after.

the: head2 ab has been threadedinto the: same untilnitmakes a snug fit'.` lmnicrometerV indicator;` mlcmbertSl" islcarriedfv by the lower" endrof the supporti ll lli and calibrated; abouti: its lowerrend",

as atite, the.calibrationsfbeingvl?` apart;I One: ointheseffmaybe marked-cerdas inl thepreviousaA construction,` andzwhichis:adaptedY to besetiini alinement.- with" the` line 4| on; thel'scale: 36, as inrthe: previous?` construction;

Two setsrlci?calibrations38a `are arranged'. tot y f read xinxopposite: directions;asy shown. above? and belowxthe line: p-f-q: inf lilig. 8 the: lower vone asl` beingiv matured'i plus'.` to indicate*V that the pitch@` diameters of the threads being tested are above those of the basic or zero; while those above the line are marked minus, indicating that the pitch diameters are below basic or zero.

In testing the accuracy of the pitch diameters of the internal threads of a member, the anvil support 40, carrying the anvil 4| and the micrometer indicator 31, is rst backed off a sufcient distance for the proper clearance of the parts, the head 3| is press ntted into the member being tested until a tight rlt is obtained, and then the support 40 is screwed inward until the anvil 4| contacts the member being tested. The outer edge of the micrometer indicator will indicate the full turns read on the scale 36, whether plus or minus, and the scale mark 38 opposite the line 4| will indicate the partial turns of the thread, whether above or below basic or normal.

The gauges may be reset as often as desired for compensating for wear due to constant use. In setting or resetting the gauge 59 the head 3| is screwed into a master internally threaded gauge head until a snug t is obtained, after which the support 4U is turned to bring the anvil 41| into contact with the head of the master gauge. The members 34 and 35 are then adjusted so that the lower or inner edge of the micrometer is at zero on the stepped scale, and the scale 38 has its zero opposite the line 4|, after which the cap nut 35 is tightened to hold the scale support 34 .in fixed position.

It is thought from the foregoing, taken in connection with the accompanying drawing, that the construction and operation of my device will be apparent to those skilled in the art, and that changes in size, shape, proportion and detail may be made without departing from the spirit and f scope of the appended claims.

7'1 I claim as my invention: 1. Agauge for testing the accuracy of the pitch diameters of tapered threaded members, comprising a threaded head for engaging the threads of said members, a support for said head, a member having an anvil thereon threaded on said support whereby said anvil may be movable relative tosaid head for engaging the inner end face of a'member to be tested, a scale supporting member, a scale on said member, a micrometer indicator member'movable with said anvil member and graduated for cooperating with said scale for indicating the relative accuracy of the threads of the tested member expressed in turns and partial turns of said last-named threads above or below a predetermined standard, and means to adjust the axial and rotative position of said indicator member relative to said anvil and lock the same in adjusted position.

2. A tapered pipe thread gauge for testing the accuracy of the pitch diameters of the threads of a threaded member, comprising an internally threadedhead, means for detachably supporting thesame, an anvil for engaging the inner end of said member, saidv anvil being threaded to said support for said threaded member, a scale having notations thereon, and a' micrometer indicator support for cooperating with said scale for inf dicating the accuracy of the pitchdiameters of said threads on said member as expressed in turns and partial turns o'f said indicator member.

3. In a gauge for testingthe accuracy of the pitch diameters of threads on a tapered threaded member, comprising an internally threaded head, a support for said threaded member, a scale on said support, an anvil for engaging the inner end of said threaded member, said anvil being 8'` threaded to said support for said threaded member, and a micrometer indicator member rotatable with said anvil and cooperating with said scale for indicating the comparative accuracy of the pitch diameters of the threads on said member. c l

4. In a gauge for testing the accuracy of the pitch diameters of tapered pipe threads, comprising an internally threaded head member, a support for said head, a scale on said support reading in terms of the turns of said tapered pipe threads both above and below a basic line, an anvil support, an anvil on said mipportfor engaging the end of a threaded member that is being tested, said anvil being threaded to said supportr for said threaded member, a micrometer indicating member carried by said anvil support, and a micrometer scale carried by said indicating member whereby the turns and partial turns above and below basic will be indicated by said indicator member and scales.

MYRoN E. sTEczYNsKI.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Husband Jan. 18, 1944 

